Nashville, N.C. — North Carolina authorities have issued nearly 200 Silver Alerts so far this year to find people with cognitive impairments, such as dementia, autism or Alzheimer's disease.

Searches can often last for days and cost thousands of dollars, but a tracking device worn like a bracelet can help find people faster, authorities said Wednesday.

Nash County recently started using the Project Lifesaver program, which has been in effect in Wake County since 2006.

Authorities say a typical search for people with a cognitive impairment, who are often prone to wander away, can last 12 to 36 hours. In a Project Lifesaver training exercise, the device helped officers find their target within 30 minutes.

"By the time we call out all of our people and equipment and do a ground search, it (costs) somewhere between $1,500 to $1,800 an hour," said Deputy Fire Marshal Chris Bissette. "We can do this search with 10 or 11 people easy, whereas before we needed 25 or 30 people and a lot of extra equipment."

Using FM radio signals, the device can track a person up to a mile away on the ground and six miles in the air. It's more effective than GPS, Bissette said.